1. Field of the Invention
The present invention relates to an apparatus for controlling a motor speed and, more particularly, to such an apparatus for controlling the speeds of the members which are driven such as a carraige and the like in a printer apparatus and the like.
2. Description of the Prior Art
Recently, various kinds of printers are used as an output apparatus for a computer and the like. Particularly, in daisy wheel printers, ink jet printers and the like, the printer is generally constituted in the manner such that the sub-scanning is performed by advancing a recording paper by a platen and the printing is done by scanning a carriage on which a print head is mounted along the platen.
With such a constitution, particularly, in the ink jet printer and the like, the speed control of the carriage on which the printing means is installed exerts an influence on the print quality. In the conventional ink jet printer and the like, a method is adopted whereby the speed of a motor to drive the carriage is detected by a photo coupler or the like which is combined with a slit plate and the like, and the motor is reversely rotated when the speed thereof is faster than a normal operating speed value and the motor is turned on when the speed is slower than the object normal operating speed value, thereby making the speed approach the object speed as quickly as possible by performing such speed control and the like.
However, according to this method, the carriage is moved while vibrating from the microscopic viewpoint, so that this makes a cause of occurrence of noise and vibration. In particular, when the printer is used in an office and the like, this noise in operation will be a large problem. To prevent this noise, a method whereby the rigidity of the portion around the driving system is improved is first considered. However, in the recent apparatus in which the small-sized and light-weighted construction is demanded, there is a disadvantage such that the weight thereof increases with an increase in rigidity.
In addition, although a method whereby the sound absorbing material is adhered to the inner wall and the like of the apparatus is considered, this is not an essential solution and there are disadvantages with respect to space use efficiency and manufacturing cost and the like.